Definitely Kakashi. He's 14 years older than the both of them, so there's no disputing it.
And I'm talking about fights that we've been presented with in the manga.It all dependeds on wether if he's talking about shown in the Manga/Anime or Just saying in General.
In that case Kakashi because he has Naruto by about 15years.
And what would make you say Kabuto? He didn't start fighting fighting until he was like, 8 or 9.I think Madara or Hashirama as far as how many battles.
For how many people they fought, probably kabuto.